xfs: fix a sloppy memory handling bug in xfs_iroot_realloc

While refactoring code, I noticed that when xfs_iroot_realloc tries to
shrink a bmbt root block, it allocates a smaller new block and then
copies "records" and pointers to the new block.  However, bmbt root
blocks cannot ever be leaves, which means that it's not technically
correct to copy records.  We /should/ be copying keys.

Note that this has never resulted in actual memory corruption because
sizeof(bmbt_rec) == (sizeof(bmbt_key) + sizeof(bmbt_ptr)).  However,
this will no longer be true when we start adding realtime rmap stuff,
so fix this now.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/libxfs/xfs_inode_fork.c b/libxfs/xfs_inode_fork.c
index 519f29d77629900886e4532c52c6ba6c16c4fd36..c4b8b153f1c84fbbbfab67489b8dc203ae631434 100644 (file)
--- a/libxfs/xfs_inode_fork.c
+++ b/libxfs/xfs_inode_fork.c
@@ -483,15 +483,15 @@ xfs_iroot_realloc(
        memcpy(new_broot, ifp->if_broot, xfs_bmbt_block_len(ip->i_mount));
 
        /*
-        * Only copy the records and pointers if there are any.
+        * Only copy the keys and pointers if there are any.
         */
        if (new_max > 0) {
                /*
-                * First copy the records.
+                * First copy the keys.
                 */
-               op = (char *)xfs_bmbt_rec_addr(mp, ifp->if_broot, 1);
-               np = (char *)xfs_bmbt_rec_addr(mp, new_broot, 1);
-               memcpy(np, op, new_max * (uint)sizeof(xfs_bmbt_rec_t));
+               op = (char *)xfs_bmbt_key_addr(mp, ifp->if_broot, 1);
+               np = (char *)xfs_bmbt_key_addr(mp, new_broot, 1);
+               memcpy(np, op, new_max * (uint)sizeof(xfs_bmbt_key_t));
 
                /*
                 * Then copy the pointers.